DFDP-2 @ 520 m, geothermal resource?

Rupert Sutherland, GNS Science and Victoria University of Wellington
John Townend, Victoria University of Wellington
Virginia Toy, University of Otago

Happy to be drilling again. Onsite shift scientists under some of our flags.16/11/14. Photo R. Sutherland.

What a great team we have at the DFDP project. About 120 scientists from 12 countries are involved in DFDP-2, and more than half of them have been working with us here onsite already.

We started in August and won’t be finished until Christmas. It’s a long time away from families and friends, but the team here has great morale. It will take at least a year to make systematic lab analyses of samples, and then another two years to do specialised analyses. It really is a big job.

We are making steady progress and passed 520 m at breakfast today (17 Nov.). We are drilling a 212 mm diameter hole on our way towards the fault, sampling and analysing rock cuttings as we go.

Geothermal conditions in the borehole have turned out to be one of the most popular talking points amongst scientists and locals. We have made 9 temperature logs of the borehole. When not cooled by circulating fluids, the borehole is at about 85°C at 500 m depth. This is about 70°C hotter than at the surface. For an average location in New Zealand, or on most other continents, the temperature increase would be about 12°C. The geothermal gradient – the rate of temperature increase with depth – is six times normal. The hot conditions underground are of scientific interest, but are also a challenge for sensitive instruments.

Is there a commercial geothermal resource here?

Our main focus is earthquake science, but there is a reasonable possibility that we have discovered a significant resource in the process.

Primary funders of the DFDP-2 project are: the International Continental Scientific Drilling Program (ICDP), the Marsden Fund of the Royal Society of New Zealand, GNS Science, Victoria University of Wellington, and the University of Otago.